1. Field of the Invention
The present invention relates to an electrophotographic copying apparatus equipped with a fixed type variable magnification system having fixed magnification scales to steppingly vary the magnification of the copy, more particularly the invention relates to a variable magnification mechanism for the optical system of the copying apparatus.
2. Description of the Related Art
The variable magnification mechanism of the copying apparatus changes the magnification of the copy from reduction to enlargement. The magnification mechanism comprises an optical system including mirrors and lenses which have to be shifted in the opposite directions for the reduction scale and the enlargement scale with respect to the position of the full size magnification.
On the other hand, the copying apparatus comprises a conveyor system for conveying the photoconductor drum and the copying papers. The conveyor system comprises a main drive motor which is able to rotate only in one direction. Therefore, it is necessary to prepare a reversible motor installed within the apparatus specially for changing the magnification in addition to the main motor so that the mirrors and lenses of the optical system are shifted to a predetermined position of the desired magnification.
However, the arrangement of such a reversible motor for changing the magnification in addition to the main motor makes the structure of the apparatus complicated and the production cost thereof high.